There was an implied aspect to my idea but it was evidently too subtle:
The button would navigate to the thread whether the thread exists or not. Only if the thread did not exist is it created, but if it does exist then the button simply navigates to present the thread. This access is critical, also if we - as @boris advocates - create the threads manually. But it would not be realistic to create the links manually. (Other than spelling problems, what should happen if the thread title already exists?)
@jeremyruston - is there any way to include a link to here, per tiddler, on tiddlywiki.com? Maybe there could, in edit view, be a toggle to globally activate them, and once activated the links appear. It could all fit in the pink ribbon, I figure.
(To bypass the problem with such a thread already existing here, the link from tw .com could e.g have a specific prefix or some hash string.)